import { useState } from 'react'
function App (){
    console.log('组件渲染')
    const [value,setValue]=useState('hello')

    function onChange(event){
        console.log(event.target.value)
        setValue(event.target.value.toUpperCase())
    }

    return (
        <input type="text" value={value} onChange ={onChange} />
    )
}
export default App
